Protection of Zinc Alloy in H3PO4 using Extract of Lantana Camara

Abstract

The inhibitive effect of lantana camara leaf extract on the corrosion of Zinc alloy in phosphoric acid solution has been studied using gravimetric methods. Inhibition increases with time and concentration of extract and temperature. This observation implies that lantana camara leaf extract is an effective and non-toxic inhibitor of the corrosion of zinc alloy. Adsorption of the extract on the surface obeyed the Langmuir adsorption isotherm. The kinetic parameter B, measured for the reaction has a high negative value which implies that lantana camara becomes more effective as the temperature increases. The free energy calculated for adsorption is small and negative in magnitude which suggests that the mechanism of adsorption is physical. The Brinell hardness test which is a measure of the tensile strength shows that lantana camara provides protection for Zn alloy in acid solutions.